Key features of UKCP09

UKCP09 provides future climate projections for land and marine regions as well as observed (past) climate data for the UK. They are the result of over seven years work by the Met Office's Hadley Centre and over thirty other contributing organisations. The projections are based on sound science and are the most comprehensive source of future climate information for the UK.

How UKCP09 fits together

UKCP09 projections are presented in a number of different ways:

1) Key Findings: This section provides maps, graphs and key findings for the UK as a whole and its administrative regions. They provide a quick way to see projected changes in the UK climate.

Resolution of the data

The projections are given at a resolution of 25km over land, and as averages for administrative, river basin marine regions.

There is greater confidence in projections at the continental scale than at local scale. Projections at the 25 km resolution are indicative in that they reflect large-scale changes, modified by local conditions such as mountains and coasts. A weather generator tool is provided that operates at 5km resolution, however there is no climate change information in the 5 km data beyond that provided at 25 km.

Emissions Scenarios

UKCP09 shows data for 3 possible emissions scenarios: low, medium and high. These are the Intergovernmental Panel on Climate Change (IPCC) scenarios B1, A1B and A1FI respectively. More information on the nature of these emissions scenarios can be found in the IPCC's
SRES report
.

It is important to remember that selecting a particular emissions scenario is a choice that will affect the projections. It is down to the user to decide which emissions scenario they think is most appropriate. It is recommended that users examine projections for all three emissions scenarios, to gain a full appreciation of changes to which they might have to adapt.

Time Periods

UKCP09 projections are given for 7 overlapping 30 year time periods. Each period steps forward by a decade, with the first time period being 2010-2039. For simplicity these time periods are referred to by the middle decade, starting with the 2020s (2010-2039) and ending with the 2080s (2070-2099).

All changes in climate variables in UKCP09 are relative to a modelled 30-year baseline period from 1961-1990. In light of this, users should note that UKCP09 projections should not be described as 'change from today's climate', as some time has passed since the baseline period.

Confidence

There is a cascade of confidence in UKCP09 climate projections. The level of confidence in the projections is affected by the scale, time period and climate variable in question. There is very high confidence in the occurrence of global warming due to human emissions of greenhouse gases.

There is relatively less confidence in local-level climate projections as compared with the continental scale. Confidence in the climate change information also depends on the climate variable in question. For example, there is higher confidence in projections of mean temperature than in those of mean precipitation.

The UKCP09 land projections take the inevitable uncertainty around future climate change into account by providing probability distributions expressing how strongly different possible outcomes are supported by current evidence. For more information on probability in the UKCP09 projections see the ''Probability in UKCP09'' page.

Need more help?

For more details about the UKCP09 climate projections, please see the Reports & guidance section.

For examples of how other organisations have used UKCP09 projections please see the Case studies.